The Diagnostic Utility of p16 Immunostaining in Differentiating Cancer and HSIL from LSIL and Benign in Cervical Cells

Promoter hypermethylation analysis of host genes in cervical intraepithelial neoplasia and cervical cancers on histological cervical specimens

BACKGROUND

DNA methylation is an essential factor in the progression of cervical intraepithelial neoplasia (CIN) to cervical cancer. The aim was to investigate the diagnostic value provided by methylation biomarkers of six tumor suppressor genes (ASTN1, DLX1, ITGA4, RXFP3, SOX17 and ZNF671) for cervical precancerous lesions and cervical cancer.

METHODS

The histological cervical specimens of 396 cases including 93 CIN1, 99 CIN2, 93 CIN3 and 111 cervical cancers were tested for methylation-specific PCR assay (GynTect®) of score and positive rate. Among them, 66 CIN1, 93 CIN2, 87 CIN3 and 72 cervical cancers were further used for paired analysis. A chi-square test was used to analyze the difference of methylation score and positive rate in cervical specimens. The paired t-test and paired chi-square test were for analyzing the methylation score and positive rate in paired CIN and cervical cancer cases. The specificity, sensitivity, odds ratio (OR) and 95% confidence interval (95% CI) of the GynTect® assay for CIN2 or worse (CIN2 +) and CIN3 or worse (CIN3 +) were evaluated.

RESULTS

According to the chi-square test trend, hypermethylation increased with severity of the lesions as defined by histological grading (P = 0.000). The methylation score above 1.1 was more common in CIN2 + than in CIN1. The DNA methylation scores in the paired groups of CIN1, CIN3 and cervical cancer were significant differences (P = 0.033, 0.000 and 0.000, respectively), except for CIN2 (P = 0.171). While the positive rate of GynTect® in each paired group had no difference (all P > 0.05). The positive rate of every methylation marker in the GynTect® assay showed differences in four cervical lesion groups (all P < 0.05). The specificity of GynTect® assay for detection of CIN2 + /CIN3 + were higher than high-risk human papillomavirus test. With CIN1 as a reference, the positive status of GynTect®/ZNF671 were significantly higher in CIN2 + : odds ratio (OR) 5.271/OR 13.909, and in CIN3 + : OR 11.022/OR 39.150, (all P < 0.001).

CONCLUSION

The promoter methylation of six tumor suppressor genes is related to the severity of cervical lesions. The GynTect® assay based on cervical specimens provides diagnostic values for detecting CIN2 + and CIN3 + .

Human papillomavirus16 E6 but not E7 upregulates GLUT1 expression in lung cancer cells by upregulating thioredoxin expression

Background and objective: E6 and E7 proteins in human papillomavirus (HPV) 16 are major oncogenes in several types of tumors, including lung cancer. Previous studies have demonstrated that both E6 and E7 oncoproteins can upregulate GLUT1 protein and mRNA expression levels in lung cancer cells. Thus, the present study aimed to investigate the main differences in the molecular mechanisms of GLUT1 expression regulated by E6 and E7. Methods: The double directional genetic manipulation and immunofluorescence were performed to explore the molecular mechanism of E6 or E7 upregulating the expression of GLUT1 in H1299 and A549 cell lines. Results: The overexpression of E6 in well-established lung cancer cell lines upregulated thioredoxin (Trx) protein expression. Notably, plasmid transfection or small interfering RNA transfection with E7 had no regulatory effect on Trx expression. As an important disulfide reductase of the intracellular antioxidant system, Trx plays important role in maintaining oxidative stress balance and protecting cells from oxidative damage. The overexpression of Trx increased the activation of NF-κB by upregulating p65 expression and promoting p65 nuclear translocation, and further upregulated GLUT1 protein and mRNA expression levels. The results of the present study demonstrated that E6, but not E7, upregulated GLUT1 expression in lung cancer cells by activating NF-κB due to the participation of Trx. Conclusion: These results suggest that Trx plays an important role in the pathogenesis of HPV-associated lung cancer, and propose a novel therapeutic target for HPV-associated lung cancer.

Reduction in immune cell number and loss of 5hmC are associated with lesion grade in cervical carcinogenesis

Tumor genome methylation is closely related to tumor immunosuppression. In the present study, we evaluated the fluctuations in DNA methylation levels, and the numbers of infiltrating T cells and their cytokines in different-grade cervical lesions. A total of 154 human cervical specimens that included LSIL (43 cases), HSIL (48 cases), and cervical squamous cancer (63 cases) were used for this study. Immunohistochemistry for 5-hydroxymethylcytosine (5hmC) and T-cell-attracting chemokines was performed, and multiplex immunofluorescence labeling was used to identify different T-cell subtypes. We found that the proportions of samples that immunostained weakly or negatively for 5hmC were increased commensurately with elevations in the severity of cervical lesions. The expression of T-cell-attracting chemokines-including CXCL9, CXCL10, and CXCL11-was positively associated with 5hmC levels, and CXCL9 was the cytokine that was most pronounced. With the progression of cervical lesions, the numbers of total T cells, CTL, and NK cells in the cervical tissues all gradually decreased. During the occurrence and development of cervical squamous carcinoma, 5hmC was gradually lost, and immunosuppression occurred in precancerous cervical lesions.

Expression analysis of p16 and TOP2A protein biomarkers in cervical cancer lesions and their correlation with clinico-histopathological characteristics in a referral hospital, Tanzania

Introduction

Biomarkers yield important information for early diagnosis of cervical cancer. However, they are rarely applied for prognosis of cervical cancer in Tanzania, where visual inspection assay with acetic acid or Lugol’s iodine and Pap test are being used as the standard screening/ diagnostic methods.

Methods

This was a retrospective hospital-based cross-sectional study that was conducted to assess cyclin-dependent kinase inhibitor (p16) and topoisomerase II-alpha (TOP2A) proteins expression among women seeking cervical cancer care at Kilimanjaro Christian Medical Centre, Tanzania between May 1, 2017 and May 10, 2018. Immunohistochemistry technique was used to detect the expressions of p16 and TOP2A proteins from the retrieved formalin-fixed and paraffin-embedded (FFPE) cervical biopsies.

Results

A total of 145 patients, with a mean age of 52.1 ± 12.9 years, were included in this study. Upon immunohistochemistry staining, 103 (71.0%) and 90 (62.1%) were p16 and TOP2A positive respectively. There was a strong association between histopathological class and p16/TOP2A expression levels (Fisher’s exact test, p<0.001). Moreover, there was a strong positive correlation between p16/TOP2A and cancerous cervical lesions (Spearman’s rank correlation coefficients = 0.833 and 0.687, p = 0.006 and 0.005, respectively). The age-adjusted odds ratio for predicting cervical cancer lesions were independently significant for p16/TOP2A biomarkers in FFPE cervical tissues [p16: OR = 1.142 (95% CI: 1.059–1.232, p<0.001) and TOP2A: OR = 1.046 (95% CI: 1.008–1.085, p = 0.015)]. Importantly, the diagnostic performance of p16 was higher than that of TOP2A in the diagnosis of cancerous lesions from non-cancerous cervical lesions (sensitivity: 97.2% versus 77.6%, accuracy: 92.8% versus 87.8%, respectively).

Conclusion

Our study has highlighted that over-expression of TOP2A is related to the grade of cervical intraepithelial neoplasia but does not predict prognosis in cervical cancer. Similarly, expression of p16 is related to degree of histological dysplasia and malignancy, suggesting its prognostic and predictive value in the management of cervical cancers. Further bigger studies are needed to validate their applications in the early diagnosis of cervical cancer.

Triaging HPV-positive, cytology-negative cervical cancer screening results with extended HPV genotyping and p16INK4a immunostaining in China

Background

Self-sampling for human papillomavirus (HPV) testing is a feasible option to improve the cervical screening coverage. However, an ideal triage method for HPV-positive self-samples does not yet exist. The aim of this study was to explore the utility of HPV genotyping and p16^INK4a immunostaining (p16) in triaging HPV-positive self-samples, focusing on HPV-positive, cytology-negative (HPCN) women.

Methods

A total of 73,699 women were screened in a cervical screening project in China via SeqHPV assay on self-samples. HPV-positive women were called-back and collected cervical sample for p16 immunostaining and liquid-based cytology, those who met any result of HPV16/18+ or visual inspection with acetic acid (VIA) + or p16+ were referred for colposcopy, and HPCN women with adequate data on p16 and pathology were analyzed. A triage strategy was considered acceptable if the negative predictive value (NPV) for cervical intraepithelial neoplasia 3 or worse (CIN3+) was 98% or more, combined with an improvement of sensitivity and specificity for CIN2+/CIN3+ in reference to the comparator, being HPV16/18 + .

Results

A total of 2731 HPCN women aged 30–64 years were enrolled, 136 (5.0%) CIN2+ and 53 (1.9%) CIN3+ were detected. Five triage strategies met the criteria: p16+; HPV16/33+; ‘HPV16+ or HPV33/58/31/35+&p16+’; ‘HPV16/33+ or HPV58/31/35+&p16+’; HPV16/18/31/33/45/52/58 + & p16+. These strategies required less or similar colposcopy referrals, and less colposcopies to detected one case of CIN2+/CIN3+, achieving favorable false positive (negative) rates to the comparator. Among them, p16 staining detected 83.1% (79.2%) of underlying CIN2 + (CIN3+) in HPCN women. Moreover, three triage strategies were favorable in sensitivity and/or specificity to the ‘HPV16/33+’ strategy: p16+; ‘HPV16+ or HPV33/58/31/35 + &p16+’; HPV16/18/31/33/45/52/58 + &p16 + .

Conclusions

Genotyping for HPV16/33 could be utilized to optimize the management of HPCN women. Moreover, p16 immunostaining, either alone or combined with extended genotypes, is more effective than HPV genotypes alone in the triage of HPCN women.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06109-4.

The expression of p16 and galectin-3 in cervical intraepithelial neoplasia (CIN) and squamous cell carcinoma (SCC) uterine cervix

Cervical cancer is the most prevalent cancer among women in India. The main cause of cervical cancer is persistent human papilloma viral (HPV) infection. HPV inactivates the pRb tumour suppressor protein; thus p16 expression, which is controlled by a negative feedback mechanism, is relatively increased. Galectin-3 is directly and indirectly connected to cancer cell activity and contributes to oncogenesis, angiogenesis, cancer progression and metastasis. Thus, the aim of this study was to study the expression of p16 and galectin-3 in Cervical Intraepithelial Neoplasia (CIN) and Squamous Cell Carcinoma (SCC) and to correlate p16 and galectin-3 expression. On hundred and eighteen newly-diagnosed untreated cases of CIN and SCC of uterine cervix were included in the study. Expression of p16 and galectin 3 was more pronounced in invasive SCC and High-grade Intraepithelial Lesion (HSIL), as compared to Low-grade Intraepithelial Lesion (LSIL).Thus, it may be used in clinical setting to monitor cervical lesions and to predict their progression.Impact statementWhat is already known on this subject? p16 overexpression is a surrogate biomarker of HPV infection and useful in evaluating HPV-associated squamous and glandular neoplasia of the lower gynaecologic tract. Increased galectin-3 expression is seen in SCC cervical, with less consistent results in CIN.What do the results of this study add? The results of our study adds to the growing literature that p16 and galectin-3 expression have direct statistically significant correlation with a degree of dysplasia and SCC cervix. Expression of p16 and galectin-3 was more pronounced in invasive SCC and high-grade intraepithelial lesion (HSIL), as compared to low-grade intraepithelial lesion (LSIL).What are the implications of these findings for clinical practice and/or further research? This correction of p16 and galectin-3 expression with degree of dysplasia and SCC cervix can be used for screening and early detection of cervical lesions and thus aid their early treatment and increased survival.

Evaluating the Performance of p16INK4a Immunocytochemistry in Cervical Cancer Screening

Purpose

When used for cervical cancer primary screening, liquid-based cytology (LBC) has a high specificity but a low sensitivity. For histological diagnosis of high-grade lesions, p16^INK4a immunostaining has proven to be useful. Therefore, our objective was to evaluate the use of p16^INK4a immuno-cytology as a primary screen and a secondary screen after primary high-risk human papillomavirus (hrHPV) screening or LBC screening.

Methods

A total of 1197 cytology slides were immuno-stained using automatic p16^INK4a staining system (PathCIN^®p16^INK4a) in two studies from cervical screening programs. In the primary screening study, 875 slides were randomly selected and analyzed for p16^INK4a. In the secondary screening study, 322 of the remaining slides were chosen by virtue of being HPV 16/18+, other hrHPV+/LBC≥ASC-US, or HPV-negative/LBC ≥LSIL. The sensitivity and specificity for detection of cervical intraepithelial neoplasia 2/3 or worse (CIN2+/CIN3+) were compared based on p16^INK4a, LBC and HPV test results.

Results

In combining two studies, there were 431 cases with biopsy pathology. They included 83 cases with CIN2+ and 41 cases with CIN3+. The p16 positivity rate increased with pathologic and cytologic severity (P<0.0001). For primary screening: p16 immuno-cytology was more specific than HPV testing and was similar in sensitivity. Also, p16 immuno-cytology compared favorably with routine LBC (≥ASC-US or ≥LSIL) in sensitivity and specificity. For secondary screening: after LBC screening, “Triaging ASC-US with p16” gave a higher specificity and a similar sensitivity as compared to the “Triaging ASC-US with hrHPV” algorithm. After HPV primary screening, p16 immuno-cytology was more specific than LBC (≥ASC-US); the calculated colposcopy referral rate was also decreased by using p16 immuno-cytology as triage. Triage of “HPV16/18 and p16” had higher specificity and similar sensitivity as compared to triage of “HPV16/18 and LBC ≥ASC-US”.

Conclusion

For primary screening, p16^INK4a immuno-cytology compares favorably to routine LBC and HPV testing. p16^INK4a immunostaining could be an efficient triage to reduce the colposcopy referral rate after primary hrHPV screening or LBC screening. Therefore, p16^INK4a immuno-cytology may be applicable as a favorable technology for cervical cancer screening.

The role of long noncoding RNA SNHG7 in human cancers (Review)

Long non-coding RNAs (lncRNAs) have been demonstrated to serve important roles in a variety of human tumor types. The lncRNA small nucleolar RNA host gene 7 (SNHG7) is associated with a variety of cancer types, such as esophageal cancer, breast cancer and gastric neoplasia. Based on previous studies that examined SNHG7 expression in tumors, it has become clear that SNHG7 modulates tumorigenesis and cancer progression by acting as a competing endogenous RNA. SNHG7 can sponge tumor-suppressive microRNAs and regulate downstream signaling pathways. In addition, overexpression of SNHG7 is associated with the clinical characteristics of patients with cancer by regulating cellular proliferation, invasion and metastasis and by inhibiting apoptosis via a variety of mechanisms of action. The function of SNHG7 in tumorigenesis and cancer progression indicates that it can potentially act as a novel therapeutic target or a diagnostic biomarker for cancer therapy or detection, respectively.

Absence of Nuclear p16 Is a Diagnostic and Independent Prognostic Biomarker in Squamous Cell Carcinoma of the Cervix

The tumor-suppressor protein p16 is paradoxically overexpressed in cervical cancer (CC). Despite its potential as a biomarker, its clinical value and the reasons for its failure in tumor suppression remain unclear. Our purpose was to determine p16 clinical and biological significance in CC. p16 expression pattern was examined by immunohistochemistry in 78 CC cases (high-grade squamous intraepithelial lesions (HSILs) and squamous cell carcinomas of the cervix –SCCCs). CC cell proliferation and invasion were monitored by real-time cell analysis and Transwell^® invasion assay, respectively. Cytoplasmic p16 interactors were identified from immunoprecipitated extracts by liquid chromatography-tandem mass spectrometry, and colocalization was confirmed by double-immunofluorescence. We observed that SCCCs showed significantly more cytoplasmic than nuclear p16 expression than HSILs. Importantly, nuclear p16 absence significantly predicted poor outcome in SCCC patients irrespective of other clinical parameters. Moreover, we demonstrated that cytoplasmic p16 interacted with CDK4 and other unreported proteins, such as BANF1, AKAP8 and AGTRAP, which could sequester p16 to avoid nuclear translocation, and then, impair its anti-tumor function. Our results suggest that the absence of nuclear p16 could be a diagnostic biomarker between HSIL and SCCC, and an independent prognostic biomarker in SCCC; and explain why p16 overexpression fails to stop CC growth.